U.S. patent application number 13/308435 was filed with the patent office on 2012-08-09 for passive bird-strike avoidance systems and methods.
This patent application is currently assigned to HONEYWELL INTERNATIONAL INC.. Invention is credited to David C. Vacanti.
Application Number | 20120200447 13/308435 |
Document ID | / |
Family ID | 45655367 |
Filed Date | 2012-08-09 |
United States Patent
Application |
20120200447 |
Kind Code |
A1 |
Vacanti; David C. |
August 9, 2012 |
PASSIVE BIRD-STRIKE AVOIDANCE SYSTEMS AND METHODS
Abstract
Systems and methods for providing passive bird-strike avoidance.
A passive L-band receiver system is located on an aircraft. The
system includes a processor and an antenna having an array of four
or more elements. The antenna configured to receive L-band signals.
The processor receives the L-band signals from the antenna,
determines if the received L-band signals indicate a target,
determines distance, direction of travel and speed of any
determined targets, determines if the target is a flock of birds
based on the determined speed and determines if a hazard condition
exists based on the distance, direction and speed.
Inventors: |
Vacanti; David C.; (Renton,
WA) |
Assignee: |
HONEYWELL INTERNATIONAL
INC.
Morristown
NJ
|
Family ID: |
45655367 |
Appl. No.: |
13/308435 |
Filed: |
November 30, 2011 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61439489 |
Feb 4, 2011 |
|
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Current U.S.
Class: |
342/29 |
Current CPC
Class: |
G01S 13/933 20200101;
G01S 7/415 20130101; G01S 13/87 20130101 |
Class at
Publication: |
342/29 |
International
Class: |
G01S 13/93 20060101
G01S013/93 |
Claims
1. A passive L-band receiver system located on an aircraft, the
system comprising: an antenna comprising an array of at least four
elements, the elements configured to receive L-band signals; a
processor configured to receive the L-band signals from the antenna
determine if the received L-band signals indicate a target;
determine distance, direction of travel and speed of any determined
targets; determine if the target is a flock of birds based on the
determined speed; and determine if a hazard condition exists based
on the distance, direction and speed.
2. The system of claim 1, wherein the processor determines if the
hazard condition exists further based on position, heading and
speed of the aircraft received from a positioning system.
3. The system of claim 2, wherein the processor receives a
reference signal from one or more L-band transmitters on the
aircraft.
4. The system of claim 2, wherein the processor determines
distance, direction of travel and speed of any determined targets
by triangulating at two different points in time of the position of
the target.
5. The system of claim 4, wherein the received L-band signal is
originated from another aircraft.
6. The system of claim 1, further comprising a housing configured
to house the antenna and the processor behind a radome.
7. The system of claim 6, wherein the housing is mounted to a
bulkhead adjacent to a weather radar antenna.
8. A method performed on an aircraft, the method comprising: at at
least four elements of an antenna, receiving L-band signals; at a
processor, receiving the L-band signals from the at least four
elements of the antenna; determining if the received L-band signals
indicate a target; determining distance, direction of travel and
speed of any determined targets; determining if the target is a
flock of birds based on the determined speed; and determining if a
hazard condition exists based on the distance, direction and
speed.
9. The method of claim 8, wherein determining if the hazard
condition exists is further based on position, heading and speed of
the aircraft received from a positioning system.
10. The method of claim 9, wherein receiving the L-band signal
comprises receiving a reference signal from one or more L-band
transmitters on the aircraft.
11. The method of claim 9, wherein the determining distance,
direction of travel and speed of any determined targets comprises
triangulating at two different points in time of the position of
the target.
12. The method of claim 11, wherein the received L-band signal is
originated from another aircraft.
Description
PRIORITY CLAIM
[0001] This application claims the benefit of U.S. Provisional
Application Ser. No. 61/439,489, filed Feb. 4, 2011, which is
hereby incorporated by reference.
BACKGROUND OF THE INVENTION
[0002] Commercial and business jets are frequently at risk of a
bird strike when they are operating near coastal areas or "flyways"
of bird migration routes. Bird strikes are exceptionally dangerous
and have been known to cause serious damage to aircraft. The pilot
is at risk of injury or death when birds strike the nose or
windshield of an aircraft.
[0003] One solution now in place for avoiding bird strikes involves
the use of fixed ground-based solid-state pulse compression radars
placed in the airport environment. The radars observe the approach
and path of flocks of birds that may encroach on airport approach
and departure routes. Airborne solutions have also involved active
radar systems that may compete with the existing weather radar and
ILS navigation antennas in the nose of an aircraft. Thus, fully
active radar is not financially or logistically viable.
SUMMARY OF THE INVENTION
[0004] The present invention provides systems and methods for
providing passive bird-strike avoidance. A passive L-band receiver
system is located on an aircraft. The system includes an antenna
and a processor. The antenna has of an array of four or more
elements configured to permit differential phase or time of arrival
measurements. The antenna is configured to receive L-band signals.
The processor receives the L-band signals from the antenna
determines if the received L-band signals indicate a target,
determines distance, direction of travel and speed of any
determined targets, determines if the target is a flock of birds
based on the determined speed and determines if a hazard condition
exists based on the distance, direction and speed.
[0005] In one aspect of the invention, the processor determines if
the hazard condition exists further based on position, heading and
speed of the aircraft received from a positioning system. The
processor receives a reference signal from one or more existing
L-band transmitters on the aircraft.
[0006] In another aspect of the invention, the processor determines
distance, direction of travel and speed of any determined targets
by triangulating at two different points in time of the position of
the target. The received L-band signal may also originate from
another aircraft.
BRIEF DESCRIPTION OF THE DRAWINGS
[0007] Preferred and alternative embodiments of the present
invention are described in detail below with reference to the
following drawings:
[0008] FIG. 1 is a block diagram of an exemplary system formed in
accordance with an embodiment of the present invention;
[0009] FIG. 2 is a flowchart of an exemplary process performed by
the system shown in FIG. 1;
[0010] FIG. 3 is a perspective view of a flock of birds in
proximity to an aircraft;
[0011] FIG. 4 illustrates a geometrical relationship between a
flock of birds and an aircraft at two points in time;
[0012] FIG. 5 is a block diagram of an exemplary passive
bird-strike avoidance system (PBSAS) formed in accordance with an
embodiment of the present invention;
[0013] FIGS. 6-1 and 6-2 are perspective views of a PBSAS package
formed in accordance with an embodiment of the present invention;
and
[0014] FIG. 7 is a perspective view of the PBSAS package of FIGS.
6-1 and 6-2 when mounted in a nose dome of an aircraft.
DETAILED DESCRIPTION OF THE INVENTION
[0015] The present invention is a passive receive-only system that
uses the normal transmissions of the traffic collision and
avoidance system (TCAS) and transponder system to provide
broad-area illumination of the entire hemisphere in front of an
aircraft with no requirement for mechanical or electronic antenna
scanning A receiver uses a phase angle-of-arrival method, common to
the TCAS system, to determine angle location of energy reflected
from bird flocks. Range to the flock is determined by timing the
flight of the aircraft's own TCAS or transponder L-band equipment
pulses using the blanking signal, for example, as a reference. The
range to the detected target may also be determined over a one
second period via triangulation with two angle-of-arrival
measurements when pulses received are not from the aircraft's own
L-band equipment.
[0016] As shown in FIG. 1, an exemplary passive bird-strike
avoidance system (PBSAS) 20 includes a receiver 32, a signal
processor 30, an antenna 34 having an array of four elements (more
than four elements may be used), and a power supply (not shown) in
a single active package that is placed on the pressure bulkhead
inside the nose radome of an aircraft 18 to permit observation of
the hemisphere in front of the aircraft 18 with the least impact to
an already present weather radar system 28 and/or an instrument
landing system (ILS) (not shown). The aircraft 18 also includes a
positioning system 26 and an L-band transponder and TCAS
system.
[0017] The PBSAS 20 provides angle-of-arrival and range-to-target
information based on reflections of illumination provided by
transmissions of the TCAS and transponder system 24. Ideally a
"time zero" T.sub.o reference pulse is provided by a transmitter of
the TCAS/transponder system 24 to the signal processor 30 via a
hardwired connection. The receiver 32 and signal processor 30
directly measure range-to-target returns using the T.sub.o
reference pulse.
[0018] The receiver 32 and the signal processor 30 identify pulses
received (and reject others if desired) via a unique identifier
encoded with received pulses. Alternatively, the receiver 32 and
the signal processor 30 process "free illumination" from other
transponders or TCAS transmissions by making only angle-of-arrival
measurements and determining range to the target (flock) via
successive angle measurements using aircraft motion (provided by
the positioning system 26, an inertial navigation system (INS) (not
shown), or a comparable device and then triangulating.
[0019] FIG. 2 illustrates an exemplary process 50 performed by the
PBSAS 20. First, at a block 54, L-band signals reflected from a
target are received at the elements of the antenna 34. Next, at a
block 56, the PBSAS 20 receives aircraft position information from
the positioning system 26 at a time associated with the reception
of the L-band signals. Then, at a block 58, the signal processor 30
of the PBSAS 20 determines position and velocity of the target
based on the received L-band signals and the aircraft position
information. At a block 60, the signal processor 30 determines if
the target is a flock of birds, if the determined velocity of the
target is below a predefined value. Then, at a block 62, the signal
processor 30 outputs the position information of the target if the
target is determined to be a flock of birds.
[0020] In one embodiment, the position information is provided to
the weather radar system 28, such as the IntuVue WXR by Honeywell,
Inc., via an existing Ethernet input or comparable data connection
(e.g., serial data link). The weather radar system 28 combines the
detected location of a flock with weather (WXR) data and performs
automatic space stabilization as the aircraft turns, climbs, etc.
If a flight management system (FMS) generated flight path and
identified flock indicate, as determined by the signal processor
30, that a bird-strike condition is about to exist, a warning icon
is displayed on a display of the weather radar system 28 and an
aural warning might sound if the threat was real and short term
(below a threshold).
[0021] In one embodiment, bird flocks are illuminated by 1090- and
1030-MHz transmissions from own aircraft 18 and other nearby
airborne aircraft. This transmission is an omnidirectional
transmission, i.e., "All Call". FIG. 3 shows 1090- and/or 1030-MHz
TCAS transmissions 70, 72 from top and bottom TCAS transmitters on
the aircraft 18. A flock of birds 76 is illuminated by at least one
of the transmissions 70, 72, thus reflecting a pulse 80 to the
antenna 34 of the PBSAS 20.
[0022] When flock illumination is performed by other aircraft, the
signal processor 30 performs range measurement via a triangulation
method--see FIG. 4. A first reflected pulse is attained at aircraft
position 90. Then at 0.2 to 1 second later a second reflected pulse
is attained at aircraft position 92. Using the position information
from a GPS (LAT, LON) or similar device, distance to the flock is
determined using triangulation, because the distance between 90 and
92 is known and so are the AZ/EL of the reflected pulses. The
signal processor 30 knows that these reflected pulses are from
another aircraft because of an identifier (ID) modulated therein.
The signal processor 30 determines that the reflected pulses are
not coming directly from the other aircraft because the result of
the triangulation shows that they are travelling at only a fraction
of the distance that the source aircraft would be travelling.
[0023] If the pulse is from the aircraft 18 as determined by the ID
within the received signal, then range measurement is determined
via time of flight based on the L-band blanking pulse (T.sub.o
reference pulse) received from the aircraft L-band transmitter(s).
In one embodiment, the PBSAS 20 is connected to a combined
AESS/ISS/L-band system.
[0024] FIG. 5 shows components of a PBSAS 20-1. An antenna 34-1
includes four elements 140-146--two rows of two. The signals (1030
and 1090 MHz) received by the elements 140-146 are selectively
processed by receiver 32-1 and/or a signal processor 30-1 in order
to produce an AZ or EL result using a phase comparison monopulse
process (i.e., interferometric scheme). The antenna 34-1 includes
four or more elements a top left (TL) element 140, a top right (TR)
element 142, a bottom left (BL) element 146, and a bottom right
(BR) element 144. The receiver 32-1 includes four subreceivers. The
subreceivers all include the same components but are connected to
the antenna elements in different manners. For example, the first
subreceiver includes a combiner 150-1 that is coupled to the TR
element 142 and BR element 144. The second subreceiver includes a
combiner 150-2 that is coupled to the TL element 140 and the BL
element 146. The third subreceiver includes a combiner 150-3 that
is coupled to the TL element 140 and the TR element 142 and the
fourth subreceiver includes a combiner 150-4 that is coupled to the
BL element 146 and the BR element 144. Each of the combiners is
connected to its own low-noise amplifier 2, which produces an
output to a respective down-converter 154. The outputs of the
down-converters 154 are converted to digital via respective
analog-to-digital (A/D) converters 156. The digitized output of the
A/D converters 156 is sent to a digital down-converter (DDC) 160
that digitally down-converts the digital output of the A/D
converters 156 for input to the signal processor 30-1. The signal
processor 30-1 analyzes the outputs of the DDCs 160, the position
information received from the positioning system 26 and/or possible
blanking time information or ID from the TCAS and transponder
system 24. The signal processor 30-1 then generates position
information of targets determined to be bird targets and sends that
to the radar system 28. A local oscillator (LO) 166 provides an LO
signal to the downcoverters 154.
[0025] In one embodiment as shown in FIG. 6, a PBSAS package 200 is
a package with microstrip antenna elements 234 located on a
receiver section 32-1. The receiver section 236 is located on a
signal processor and power supply section 240. The antenna elements
234 are covered by a radome 244.
[0026] In one embodiment, the PBSAS package 200 is located at a top
section of a forward pressure bulkhead 250 above a weather radar
antenna 254 installation, if present (FIG. 7), and above an
instrument landing system (ILS) antenna 256 if no weather radar
antenna is present. Alternately, two PBSAS passive packages 200 are
located on each side of a WXR antenna gimbal 260 in the radome when
the location above the weather radar antenna 254 is occupied. The
forward-looking PBSAS package 200 provides detection in the general
direction of travel with wide field of view--greater than or equal
to 60 degrees in azimuth and elevation.
[0027] In one embodiment, the flock location information generated
by the PBSAS 20 may be supplied to a data bus for presentation on
an enhanced ground proximity warning system (EGPWS) or traffic
collision avoidance system (TCAS) displays.
[0028] While the preferred embodiment of the invention has been
illustrated and described, as noted above, many changes can be made
without departing from the spirit and scope of the invention.
Accordingly, the scope of the invention is not limited by the
disclosure of the preferred embodiment. Instead, the invention
should be determined entirely by reference to the claims that
follow.
* * * * *